On 6 June 2012, the apnea diver Herbert Nitsch sought to improve his own world record in freediving by another 100 feet -- to 800 feet (244 m). The record attempt off the Greek island of Santorini was to only be the beginning of his "1,000 feet" project. . Unconscious, he had to be brought to the surface by rescue divers -- after reaching a depth of more than 818 feet...